The overall objective of this contract is to develop psychometrically robust Executive Function measurement tools that are accepted by the neurology clinical trials and clinical research communities. Specific goals of the contract are: 1. To develop a core set of tasks that will address specific domains of Executive Function that is universal to patients with chronic neurological disorders (for example: stroke, traumatic brain injury, neurodegenerative disorders, epilepsy, etc.). 2. To integrate the specific following characteristics in the NINDS Executive Function test battery: o focused on two or more of the following six domains: inhibition (response suppression;interference resolution);working memory (manipulation and maintenance of information;temporal organization (time &place);set shifting (mental flexibility);self monitoring (behavioral awareness, insight);abstraction (rules, categories). o modifiable (depending on individual protocols or paradigms and individual differences) o portable (battery that can be administered in emergency room;physician offices) o programmable;replicable (flexible across laboratories) o usable across age groups o adaptable for clinical trials o utilizes naturalistic situations (virtual reality) o includes functional outcomes (sensitive to treatment, training, drugs) The NINDS is seeking an innovative approach to Executive Function measurement that will be responsive to the needs of researchers in a variety of neurological disorders and settings, with a particular emphasis on measuring outcomes in clinical trials. Determining criteria for acceptability to the neurology research community prior to specific domain tasks development and evaluating the acceptability to researchers of the final battery will be essential to successful completion of these goals.